Patent Document 1 discloses a hydraulic braking system including (i) a plurality of brake cylinders, (ii) a high pressure source including a pump device, (iii) a common passage to which the plurality of brake cylinders and the high pressure source are connected, (iv) a master cylinder connected to brake cylinders for front left and right wheels via respective master cut-off valves, (v) a pressure-increase linear valve and a pressure-reduction linear valve configured to control a hydraulic pressure in the common passage, and (iv) an anti-lock control valve device provided between the common passage and the plurality of brake cylinders and including a plurality of anti-lock control valves.
In the normal braking in this hydraulic braking system, in a state in which the master cylinder is isolated from the respective brake cylinders of the front left and right wheels by the respective master cut-off valves, the pressure-increase linear valve and the pressure-reduction linear valve are controlled to control the hydraulic pressure in the common passage to control hydraulic pressures in the respective plurality of brake cylinders in common. In anti-lock control, the pressure-increase linear valve and the pressure-reduction linear valve control the hydraulic pressure in the common passage, and the plurality of anti-lock control valves control the hydraulic pressures in the respective brake cylinders, individually, but an opening and closing switching pressure of each of the pressure-increase linear valve and the pressure-reduction linear valve is greater than in the normal braking. As a result, the pressure-increase linear valve is opened, and the pressure-reduction linear valve is closed, thereby suppressing change in the hydraulic pressure in the common passage due to opening and closing operations of the anti-lock control valves.